The present invention relates to an improved, high-explosive, land mine containing a plurality of explosive charges, and improved fuze means for initiating the charges in a particular sequence, in response to a signal produced by the presence of a tank or other armored vehicle.
Bearce U.S. Pat. No. 3,216,354, granted Nov. 9, 1965, disclosed a land mine, intended to be placed underground, including a short cylindrical housing containing a main high explosive shaped charge having a lower flat surface and an upper dish-shaped surface which is lined with a metal plate or cover member of frangible or malleable material. An auxiliary clearing charge is carried by a removable top plate of the housing (above the shaped charge) together with a primer and an impact fuze mechanism adapted to be actuated by a vehicle to actuate the primer to initiate the clearing charge. Explosion of the clearing charge (1) blows the overburden and the top plate off the housing to expose the shaped charge, and (2) actuates a firing mechanism which initiates a delay charge which, after a predetermined time interval, initiates the lined shaped charge.
In a copending application of Allen E. Stern, Ser. No. 627,174, filed concurrently herewith assigned to the same assignee, the land mine of the Bearce patent is modified and improved by: (1) making it double-ended, with a concave surface on each end of the main charge lined with a hardened metal missile plate and a removable external end wall at each end of the housing, whereby the mine can be carried into the air by an artillery projectile, for example, ejected over the desired area, deployed from the air, and come to rest by gravity on either end thereof, instead of being placed underground; (2) positioning a clearing charge at each end, between the main charge and the end wall; and (3) providing means including a gravity-controlled switch for initiating the upper clearing charge only, and thereby removing the upper end wall only, in response to a firing signal, e.g. derived from a proximity fuze, prior to initiation of the main charge of the mine.
In Wolterman U.S. Pat. No. 3,891,162, granted June 24, 1975, a projectile, having a main charge and a supplemental charge, is provided with a fast firing train, including an elongated flash tube, for first initiating the supplemental charge, a slow firing train, including a delay element and a detonator radially aligned with an explosive lead in armed position, for subsequently initiating the main charge, and a single igniting means for simultaneously initiating the two firing trains. No means for interrupting and completing the fast firing train is provided.
An object of the present invention is to provide a new and improved fuze means for first initiating a supplemental explosive charge and then initiating the main charge in a high explosive land mine.
In accordance with the invention, a land mine containing a main high explosive charge and a suplemental explosive charge is provided with improved fuze means for initiating the supplemental charge and subsequently initiating the main charge after a predetermined delay, comprising: a fuze body containing a fast firing train connected to the supplemental charge, a slow firing train, including a delay element, connected to the main charge; an arming member slidable in the fuze body between a safe position and an armed position, at least a portion of each firing train being carried by the arming member in such manner that both firing trains are completed by the slider in its armed position only, and means for initiating the two firing trains substantially simultaneously in response to a single firing signal.
Preferably, the mine is aerially-deployed and double-ended, with a supplemental clearing charge at each end, as in the Stern application, and the fast firing train is selectively connected to the upper clearing charge only, by means of a gravity-controlled switch.
In one embodiment, the delay element is a delay detonator forming part of the slow firing train and initiated simultaneously with a fast-firing detonator in the fast firing train. In another embodiment, the slow firing train is initiated by the first firing train. Each embodiment includes a gravitycontrolled switch disclosed and claimed in a copending application of Ferdinando V. Dukic, one of the inventors of this application, Ser. No. 627,175, filed herewith, assigned to the same assignee.